According to Transportation for America, an advocacy coalition, by 2015 more than 15.5 million Americans 65-plus will live in areas where public transportation service is poor or nonexistent.

Getting older nondrivers where they need to go could become a national conundrum.

Some communities and organizations are pursuing local solutions. For instance, the trailblazing nonprofit Independent Transportation Network, launched in Maine in 1995, transports people by using a combination of paid and volunteer drivers. Now serving 27 localities, it provided its 500,000th ride last December. Other nonprofits, for-profit companies and municipal and county agencies — often working together — are scrambling to fill the transportation demand.

Here are four innovative initiatives around the country that are getting nondrivers where they need to be.

California: SilverRide

At this San Francisco-based, for-profit transportation company — now expanding into Southern California — drivers are also real companions.

How It Works: The company first meets clients and learns about their interests, often planning outings around them. Drivers may take a client to run errands and then have lunch together. Or pick up one friend at a senior community, another at a private home and go see a movie. Once a week, the company has a group event, such as a barbecue in the park. Cofounder Jeff Maltz says SilverRide (415-861-7433) is "about a repeat experience." Rides average $85 round trip, no tipping.

Dashboard: Since 2007, SilverRide has provided more than 150,000 outings for 3,200-plus clients. Seventy percent of the time, drivers join riders in activities. Average rider age: 85.

The Talk: SilverRide has accolades galore, including the 2009 American Society on Aging national Business of the Year award. "We enable clients to have meaningful experiences outside the home and continue to lead normal lives," says Maltz.

Jason Laveglia, 47, a Web consultant in Scottsdale, Ariz., is a long-distance caregiver to his mother, Ila Dicks, 75. Neither he nor his brother could be in San Francisco for her recent birthday, so they had SilverRide take her to lunch and arrange for a cake. The driver sent photos to Laveglia's phone of Dicks blowing out the candles. The company gives families a trip report not only about the outings, but also about the client's mood and any concerns. "I get a 360 view of what happened, and feel like I'm in the loop," Laveglia says. "It's peace of mind that she can have the freedom and I know that she's safe."

South Carolina: Lower Savannah Council of Governments (LSCOG)

Located in Aiken County, S.C., the Lower Savannah Council of Governments (1-866-845-1550)is a one-stop resource center helps solve transportation quandaries and other aging-related issues.

How It Works: Residents can call the center and ask a mobility manager about a bus schedule, get help with directions or request a specific trip.

Dashboard: The center fields more than 12,000 calls annually in the popular retirement area; while the general population grew by 12 percent from 2000 to 2010, the 60-plus demographic increased 44.2 percent. Municipalities nationwide are interested in replicating the model.

The Talk: "If you need transit help, you probably need other things to live an engaged, independent life in your community," says Lynnda Bassham, director of human services for LSCOG.

One year, a daughter called wanting to get her mother from a nursing home to a family Thanksgiving dinner but couldn't fit a wheelchair into her car. Mobility manager Rhonda Mitchell found an ambulance company to transport her mom for a small fee. "Most calls are from people who don't qualify for Medicaid and need transportation to medical appointments," says Mitchell. "While we're talking, we let them know of services for personal use, too. It seems to lift their burden."

Maryland: Ride Partners

Ride Partners (410-544-4800), part of the nonprofit Partners in Care Maryland, is an all-volunteer program that covers rural, urban and suburban areas.

How It Works: The program runs on a time bank system. Drivers get credit for "chauffeuring" and can dip into the bank if they need a ride. Passengers give back, if able, and get bank credit, too. They might answer the office phone, bake for an open house, knit clothing for the organization's boutique or volunteer there.

Dashboard: 2,300 members ages 50 to 105; 400 drivers and 9,000 rides covering more than 100,000 miles a year.

The Talk: "No matter how old people are, they have talents they can share," says Barbara Huston, president and CEO of Partners in Care Maryland. "The way drivers and riders participate makes everyone equal." Christine Jennings, 57, never drove and was dependent on cabs when she needed back surgery. Ride Partners began taking her to the doctor. "This program saves me a lot of money," says Jennings, "and makes me feel secure knowing someone is waiting for me."

South Dakota: River Cities Public Transit (RCPT)

River Cities Public Transit (605-945-2360), a private, nonprofit outfit in a mostly rural, 11-county area in South Dakota includes Pierre, the capital, and the Lower Brule and Cheyenne River Sioux Indian reservations. Rides run 24/7 around Pierre; four job shuttles transport commuters up to 80 miles away.

How It Works: On workdays, rural commuters meet and ride in a van or small bus to the city ($3 to $9 round trip). During the day, the vehicles take children to activities or, for $1.55 ($1 if 60-plus), transport older adults to senior centers, nutrition programs and other venues.

Dashboard: In 10 years, ridership has quadrupled.

The Talk: "Our service is life-saving and life-enhancing," says Ron Baumgart, RCPT's executive director. Riders can get a lift to dialysis, plan to work late or see a grandchild in an evening play. Five days a week, Judy Rada, 62, gets picked up at her apartment at 6 a.m. and driven to her job at Wal-Mart. Then RCPT brings her home at 4 p.m. "It's awesome — they help me right into my building," says Rada, who uses a wheelchair. "I wouldn't survive without this service."